The subject matter disclosed herein relates to single photon emission computed tomography (SPECT), and more particularly to a system and method for aligning collimators with detectors in medical imaging.
A wide range of imaging techniques are known and currently in use, particularly for medical diagnostic applications. One such technique, SPECT, relies on the emission of gamma rays during the radioactive decay of a radioisotope (or radionuclide), commonly administered in the form of a radiopharmaceutical agent that can be carried, and in some cases, bound to particular tissues of interest. A SPECT scanner detects the emissions via a gamma camera that typically includes a collimator, a scintillator, and a series of photomultiplier tubes. The collimator allows only emissions in a particular direction to enter into the scintillator. The scintillator converts the gamma radiation into lower energy ultraviolet photons that impact regions (pixels) of the photomultiplier tubes. These, in turn, generate image data related to the quantity of radiation impacting the individual regions. Image reconstruction techniques, such as backprojection, may then be used to construct images of internal structures of the subject based upon this image data.
While such systems have proven extremely useful at providing high quality images with good diagnostic value, further refinement is needed. For example, a system may include a gamma camera with two detectors. Each detector uses a collimator to allow only certain emissions. When collimators are attached to the detectors, the collimators need to be aligned with the detectors and each other for proper operation. Furthermore, the alignment position may change due to such things as settling of the floor, temperature changes, floor deviations, and use of collimators on different system. Manual alignment procedures may be performed by trained service personnel to enable the collimators and detectors to be aligned. However, the number of service personnel available to perform alignment procedures may be limited, and the cost for service personnel to perform the alignment procedures on a regular basis may inhibit routine alignment. Therefore, a system that automatically assists in aligning the detectors and collimators may be desirable.